Film Speed Control

The first control on your camera that we need to talk about is the film speed setting.
If you are using ASA 100 film, set the control to 100.

Set your fstop (aperture), that ring around your lens with setting marks like "5.6" and "2.8", to its most open position. The most open position will be the lowest number on the ring.  That is the setting that will let in the most light.  Think of it as the BIG HOLE.  the smallest setting, will be the largest number on the ring, like 16 or 22.  Think of this as the little PIN HOLE.  Now set your shutter speed to 125.
Take a meter reading on something.
Now change your film speed control to other settings and check the meter readings.
If you were using a slower speed film what would your shutter speed have to be?
If you were using faster film?
This becomes important to know because there is a limit to how slow a shutter speed you can hand hold.
You should know your limitations and use a tripod when necessary.

Shutter Speed and Aperture
The shutter speed you select determines how long the film will be exposed to light.  Your aperture (fstop) setting will determine just how much light will enter the camera during that time.
As a compositional consideration, your shutter speed, in conjunction with your aperture, has two major functions.
1.  Stop or show action
2.  Allows for depth of field through wide (with fast shutter speed) or small (with slow shutter speed) aperture.

The aperture or fstop is the hole size that light passes through when the shutter is opened.  A wide aperture like 2.8 lets in lots of light so you can use a fast shutter speed which allows you to stop the action or shoot in low light.  A small aperture like f16 will require a slower shutter speed allowing you to show action (blur) or have more of the picture in focus, or shoot in bright light.

And, by the way, as a side note, another concept is depth of focus.

Set your film speed control to the proper setting and take a picture of a group of things.
Fill the frame with the group and focus on the center piece.

Now step back 10 feet and shoot it again, still focusing on the center piece, but this time the subjects will not fill the frame.
Once more at 20 ft.
What we have just done is an exercise in depth of focus.  It is our natural instinct to fill the frame with the subject.  This is good but sometimes the subject is too small to get a good focus on all the elements of the image.  When you see your photos, check the focus on the outboard elements at the different distances.  If the picture you are taking and the composition you are envision require all the elements to be in focus you must choose to not fill the frame.  When you blow-up (enlarge the photo) you can eliminate everything surrounding the elements.

The photo of the empty film boxes is a good example of this.  If a messy look is what you want, the shallow focus and shadows all add to achieving that.



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